Anomalous spin splitting of electrons in type-II InSb quantum dots in InAs.

Magnetooptical studies of heterostructures with type-II InSb quantum dots in the InAs matrix grown by molecular beam epitaxy are carried out. Unusual behavior of magnetophotoluminescence from quantum dots measured in the Faraday geometry in the samples with multiple planes of quantum dots is found. Specifically, the peak with σ− polarization, which corresponds to transitions of electrons with s = +1/2, has a higher energy than the σ+ peak corresponding to s = −1/2, which contradicts the negative value of the electron g factor both in the InAs matrix and in the InSb quantum dot. The effect can be interpreted as the result of competition of two channels of radiative recombination, which differ by the initial states of electrons belonging either to the InSb quantum dots or to shallow-level donors in the InAs matrix. [ABSTRACT FROM AUTHOR]